Pops occur when lumber shrinks and exposes the shank of a nail or screw. Pressure on the loose drywall panel causes the head of the fastener to pop through. When installing drywall, make sure the screws penetrate the stud by at least 5/8 inch; nails should penetrate the stud by at least 7/8 inch. Don’t set the fastener too deep; tearing the paper surface also reduces the holding power of the fastener, Do it right the first time.
Article This Old House 2013 by Joe Hurst - Wajszczuk
When the wood shrinks it basically strangles the nails causing pressure and the nail and sometimes (but not often) the screw will pop. Sudden changes in air pressure can also cause them to loosen. Being proactive is the best way to avoid nails popping out.
What to do?
make sure the framing is dry before nailing drywall.
use screws! Not nails.
use quality products
Above answers are true. Wood moves and nails (at least drywall nails) do not work as effective as screws. It is extremely important to babysit your drywall contractor to ensure screws are used. Drywallers are notorious in my area for being lazy and not using screws. Many new construction homes have this problem believe it or not.
when lumber shrinks and exposes the shank of a nail or screw
